From b8d73731779bce53e940e347e71851d45c9c6cdc Mon Sep 17 00:00:00 2001
From: Olivier Parcollet <olivier.parcollet@cea.fr>
Date: Fri, 21 Feb 2014 21:00:38 +0100
Subject: [PATCH] arrays : fix auto_assign for chains assignment.

A(i_)(om_) << ...
for A an array of gf was not working.
Modified the auto_assign of arrays to handle the case when the object
in the array is itself autoassigned.
Using the model of std::vector adapter for clef, which works.
Also fixed the gf for a little details (gf_impl is usually in the expression tree, not gf).
---
 triqs/arrays/impl/indexmap_storage_pair.hpp | 19 ++++++++++++++++++-
 triqs/gfs/gf.hpp                            |  9 +++++++++
 2 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/triqs/arrays/impl/indexmap_storage_pair.hpp b/triqs/arrays/impl/indexmap_storage_pair.hpp
index 0cc80e98..5bc3c7a2 100644
--- a/triqs/arrays/impl/indexmap_storage_pair.hpp
+++ b/triqs/arrays/impl/indexmap_storage_pair.hpp
@@ -260,7 +260,24 @@ namespace triqs { namespace arrays {
       return make_expr_call(std::move(*this),args...);
      }
 
-    template<typename Fnt> friend void triqs_clef_auto_assign (indexmap_storage_pair & x, Fnt f) { assign_foreach(x,f);}
+     // ------------------------------- clef auto assign --------------------------------------------
+
+     // For simple cases, it is assign_foreach. But when f(args...) is a function from a clef expression
+     // we make a chain call like cf clef vector adapter
+     template <typename Function> struct _worker {
+      indexmap_storage_pair &A;
+      Function const &f;
+      template <typename T, typename RHS> void assign(T &x, RHS &&rhs) { x = std::forward<RHS>(rhs); }
+      template <typename Expr, int... Is, typename T> void assign(T &x, clef::make_fun_impl<Expr, Is...> &&rhs) {
+       triqs_clef_auto_assign(x, std::forward<clef::make_fun_impl<Expr, Is...>>(rhs));
+      }
+      template <typename... Args> void operator()(Args const &... args) { this->assign(A(args...), f(args...)); }
+     };
+
+     template <typename Fnt> friend void triqs_clef_auto_assign(indexmap_storage_pair &x, Fnt f) {
+      foreach(x, _worker<Fnt>{x, f});
+     }
+     // template<typename Fnt> friend void triqs_clef_auto_assign (indexmap_storage_pair & x, Fnt f) { assign_foreach(x,f);}
 
     // ------------------------------- Iterators --------------------------------------------
     typedef iterator_adapter<true,typename IndexMapType::iterator, StorageType> const_iterator;
diff --git a/triqs/gfs/gf.hpp b/triqs/gfs/gf.hpp
index a995f222..9545524a 100644
--- a/triqs/gfs/gf.hpp
+++ b/triqs/gfs/gf.hpp
@@ -431,6 +431,15 @@ namespace gfs {
   }
  };
 
+ // in most expression, the gf_impl version is enough.
+ // But in chained clef expression, A(i_)(om_) where A is an array of gf
+ // we need to call it with the gf, not gf_impl (or the template resolution find the deleted funciton in clef).
+ // Another fix is to make gf, gf_view in the expression tree, but this requires using CRPT in gf_impl...
+ template <typename RHS, typename Variable, typename Target, typename Opt>
+ void triqs_clef_auto_assign(gf<Variable, Target, Opt> &g, RHS const &rhs) {
+  triqs_clef_auto_assign( static_cast<gf_impl<Variable, Target, Opt, false, false>&>(g), rhs);
+ }
+ 
  // --------------------------The const View class of GF -------------------------------------------------------
 
  template <typename Variable, typename Target, typename Opt>